Double arrow markers are too aggressively removed

[erikvullings]

Describe the bug
In Inkscape, I create a simple line with double arrows, i.e. a marker at the start and at the end. After optimizing the SVG, one of the arrows is removed. In particular, the marker-end refers to a url, but its definition has been removed.

To Reproduce
Steps to reproduce the behavior:

1. Open the attached SVG
2. svgo double_arrow_test.svg
3. Open the optimized error again, and notice that one marker is removed.

Expected behavior
Both arrows should be kept.

Screenshots
Original

After optimizing

Desktop (please complete the following information):

• SVGO Version 3.0.2
• NodeJs Version 16.18.1
• OS: Ubuntu 20.04 on WSL2

Original Inkscape file:

[Darkproduct]

I just had the same issue. It looks like the bug is in the cleanupIds Plugin. Disabling this feature fixes the missing markers.

Here is a working config:

module.exports = {
  multipass: true,
  plugins: [
    {
      name: 'preset-default',
      params: {
        overrides: {
          // viewBox is required to resize SVGs
          // @see https://github.com/svg/svgo/issues/1128
          removeViewBox: false,
          // Removes markers
          // @see https://github.com/svg/svgo/issues/1721
          cleanupIds: false,
        },
      },
    },
  ],
};

[hashimaziz1]

Enabling the prefixIds plugin would likely be a better solution for this that would allow cleanupIds to remain enabled.

[SethFalco]

Hey! Thanks for reporting the issue and providing an example.
This has been incidentally resolved in a recent PR. (#1795)

The fix will be released in v3.0.3.